Corsair Publishes 875P Memory Benchmark Report

Corsair receives a lot of questions about memory performance, howto config systems, which timings will get me the best performace, and so on. So Corsair decided to do a BIG test. They used a P4C800 Deluxe Canterwood motherboard with P4 2.4GHz processor, ATI 9800 128MB graphics card, and 1GB of Corsair TWINX memory. They tested the difference between single and dual channel mode, and memory clock speeds rating from DDR400 to DDR533 at different timings with their test sytem. But unfortunately they only used synthetical benchmarks like SiSoft Sandra, and did not include any real life tests like PiFast, Quake 3 or UT2003. Anyway here is the full article :

Corsair 875P Memory Benchmark Report, July 2003
We get lots of questions about memory performance, about how to configure a system, about what effect memory latency settings have, and so forth. So, in order to help out a little, we have compiled this report, which should give you a glimpse of the results that we have attained here in our lab. Note that we don't try to tweak the system for maximum score, we just fuss with the memory. So your results may vary!

This benchmarking exercise allowed us to draw three significant conclusions. First, it confirmed for us that in current 875P (Canterwood) based systems, memory clock speed significantly outweighs memory latency settings as the primary performance factor in the memory subsystem. More simply put, you are better off clocking the memory as fast as it will go (assuming the CPU/FSB will go that fast) at the expense of looser latency settings, as opposed to cranking the latency settings as tight as they will go (as is the case with Nforce2, for instance).

Second, obviously, is that dual channel memory provides significant performance improvements over single channel memory. So, it is therefore very important to populate both memory channels in dual channel boards.

The third thing that the scores confirmed for us is that the memory bandwidth of the 875P matches up very well with the processor performance. Memory bandwidth, in general, is keeping up pretty well with the CPU in these systems.

Test Platform Overview
The benchmarks were performed on a system which we felt was similar to systems that enthusiasts are building today. The setup included an Asus P4C800 Deluxe motherboard, P4 2.4GHz processor, ATI 9800 128MB graphics card, and 1 GByte of Corsair TWINX memory, consisting of a matched pair of 512 MByte modules. Testing was done with the system configured for both single channel and dual channel operation, and a wide variety of latency settings and clock speeds were examined.

The Benchmarks
We focused our testing on two types of benchmarks. The first benchmarks were common benchmarks that attempt to measure memory bandwidth. These benchmarks included Aida32, PCMark 2002, and SiSoft Sandra Memory benchmarks. The second set of benchmarks were designed to measure overall system performance. These tests included 3dMark 2001 SE, 3dMark 2003, PCMark 2002 CPU, and SiSoft Sandra CPU. We could have run more, of course, but we simply ran out of time!

Bandwidth Benchmarks
The following benchmarks focus on measuring memory bandwidth:

Benchmark 1A: AIDA32

Benchmark 2A: SiSoft Sandra Memory

Benchmark 3A: PCMark 2002 Memory

System Benchmarks
The following benchmarks are designed to measure overall system performance:

Benchmark 1B: 3dMark, 2001SE and 2003 Versions

Benchmark 2B: SiSoft Sandra CPU

Benchmark 3B: PCMark 2002 CPU

Summary of Results
Aida32, SiSoft Sandra, and PCMark 2002 memory testing all show very consistent results. The improvement in memory bandwidth when moving from single channel to dual channel is substantial, as we expected. The improvement ranged from a minimum of around 15% in PCMark, to over 40% in Sandra. This result was much more pronounced in 875P systems than it was in previously benchmarked Nforce2 systems.

3dMark 2001SE seems to provide the best measure of overall performance, indicating that the improvement in memory bandwidth offered by dual channel memory generally results in a 3% to 5% increase in overall system performance. This is about the same as increasing the clock rate of the CPU (and front side bus) by 25 to 33 MHz. PCMark 2002 CPU also seems to show very rational results. It shows negligible difference in performance between single and dual channel, indicating perhaps that the benchmark is largely independent of memory bandwidth - a logical result if it operates completely out of the processor's cache.
Some results were a bit surprising, starting with 3dMark 2003 - it is tough to tell from these results just what they are measuring, but it certainly has little to do with either memory bandwidth or CPU speed! Generally, one would expect that a 33% increase in CPU (and front side bus) operating frequency would result in more than a 4.3% increase in performance! Sandra CPU scores also baffle, with single channel often (but not always) outperforming dual channel, and performance occasionally decreasing as clock speed increases. The results here suggest that perhaps the algorithm that is used to calculate the score uses some assumptions that simply are not valid at these speeds.

Conclusions
The results of the memory bandwidth benchmarks offer no big surprises. The great benefits of dual channel memory are clearly seen here, offering substantial performance increases across the board. These benchmarks also provide a useful gauge of the effect of latency settings and clock speed on the overall bandwidth of the memory subsystem. In general, we find that as the system gets faster, latency settings begin to diminish in importance in system performance, as greater results can generally be obtained by clocking the memory (and the processor along with it) to the maximum possible frequency.

When we move to the system benchmarks, we start to see some interesting and intriguing results. We believe this is an indication that modern memory subsystems are doing a pretty good job of keeping the processor well-fed with instructions and data.